July 25, 2013\u2014The Ivanpah solar plant in California's Mojave Desert is the largest of its kind under construction in the world. Developer BrightSource says it will provide solar electricity to 140,000 homes when operational. And while it displaced threatened desert tortoises, it apparently has not significantly harmed their population.

\"Unlike photovoltaics that convert sunlight to direct current to produce electricity, we actually use the sun's energy to focus sunlight onto a boiler to create high temperature, high pressure steam, which is then used to turn a turbine to generate electricity.\"

\"What I'm standing underneath is a heliostat, which is a fancy word for a thing that holds two mirrors. And those mirrors are used to reflect sunlight onto the boiler that you see right behind me.\"

\"What you are looking at here\u2013totaling 392 megawatts gross output\u2013is the equivalent of a medium-sized natural gas plant.\"

SOUNDBITE\u00a0 Dave Beaudoin, Site Manager for Solar Partners

\"We've eliminated the fossil fuels and we're using the sun's energy to boil the water to make the steam.\"

SOUNDBITE:\u00a0 Larry LaPre, Bureau of Land Management Biologist

\"It's a tradeoff. You don't have the nuclear waste lasting for tens of thousands of years. And you don't have the CO2 emissions from coal and gas-fired plants. But you take up a lot of space. Displace a lot of plants and wildlife.\"

SOUNDBITE: Ed LaRue, Biologist, Desert Tortoise Council

\"There's thousands and thousands of square miles out here that had been crawling with tortoises back in the '40s and '50s that no longer have tortoises. And, to find a place that still has that abundance of tortoises on it and to develop it was probably the real shame of it. The problem is now we've got this shift where we're taking 5 square miles of public lands and putting mirrors on it, and it'll never come back.\"

SOUNDBITE: Joseph Desmond, Sr. VP Marketing, BrightSource Energy

\"You're always talking about tradeoffs. So the question is: can you develop a project and still be environmentally responsible and do it in a way that actually enhances the environment.\u00a0 We found, when we came on site, within the boundaries, roughly 173 tortoises. Those tortoises were moved into a nursery where they were protected and kept. We've found now is that after this time there is no statistically significant difference in the survival or mortality of those tortoises that have been moved.\"

SOUNDBITE: Larry LaPre, Bureau of Land Management Biologist

The ones you rescued are moved out to the side and they're now living with the resident tortoises... another thing, they try and go back and they're found walking along the fence of the power plant.\"

SOUNDBITE: Ed LaRue, Biologist, Desert Tortoise Council

\"I think the one ray of hope that I see is that in the desert tortoise natural area, they've completely fenced that 40 plus square miles and it's the only place I'm aware of where tortoises are reproducing.\"

SOUNDBITE: Joseph Desmond, Sr. VP Marketing, BrightSource Energy

\"When you talking about fossil fuels, you have to factor in the land use for exploration, extraction, processing and transportation.\u00a0 Here, we have a project that actually collects the energy and then converts to electricity all within a single location.\"

\"People sometimes forget that this is actually a very efficient utilization of a sustainable energy resource.\"

\"So a project of this size will avoid nearly 400,000 metric tons of carbon each year that otherwise would have been emitted.\"